15min:

MENG-LING CHEN, KWANG-HWA LII AND BOR-CHEN CHANG, Department of Chemistry, National Central University, 300 Jhongda Road, Jhongli 32001, Taiwan.

We have studied the spectroscopy of luminescent crystals containing rare earth elements such as KEuGe₂O₆, Cs₃EuSi₆O₁₅, K₄[(UO₂)Eu₂(Ge₂O₇)₂], and R₂(C₈H₁₀O₄)₃ (R= Y, Tb, or Eu). The emission and excitation spectra of these compounds were recorded at ambient temperature. These spectra are consistent with the structures which were determined by single crystal X-ray diffraction. Crystals containing hybrid luminescent centers were also synthesized and interesting energy transfer mechanisms were observed. For example, dramatic luminescence quenching was found in KEu_xNd_1-xGe₂O₆ (x= 0.98, 0.96, 0.94, and 0.84) as well as in Cs₃Eu_0.98Nd_0.02Si₆O₁₅, while different compositions of Y_xEu_yTb_2-x-y(C₈H₁₀O₄)₃ exhibit different emission colors. Emission lifetimes were also measured for these compounds, and the results shed light on the energy transfer mechanisms. Detailed results of our research will be presented.